Anticonvulsants

An understanding of the pharmacology of anti-depressant, anti-psychotic, anti-convulsant, and anti-Parkinsonian medication

Anticonvulsants work via a number of different mechanisms:

Sodium Channel Blockers

Sodium channel blockers:

Stabilise the inactive state of the channel, preventing return to the active state and prevent generation of further action potentialsThis halts post-tetanic potentiation and limits the development of seizure activity.

May also have Class I antiarrhythmic propertiesDue to Na+ blocking effects.

Include:

Phenytoin

Carbamazepine

Lamotrigine

GABA Mediators

GABA is the key inhibitory neurotransmitter in the CNS. GABA mediators:

Enhance the effect of GABAMultiple potential mechanisms:

Direct GABA-receptor agonistse.g. Benzodiazepines and phenobarbital.

Positive allosteric modulatione.g. Propofol and thiopentone.

GABA reuptake inhibitione.g. Tiagabine.

GABA transaminase inhibitione.g. Vigabatrin.

Increase GABA synthesise.g. Sodium Valproate.

Glutamate Blockers

Glutamate is an important CNS excitatory neurotransmitter. Glutamate antagonists:

Are generally avoided due to their side effect profile, which includes psychosis and hallucinations